U.S. patent number 11,168,199 [Application Number 16/339,505] was granted by the patent office on 2021-11-09 for polycarbonate resin composition.
This patent grant is currently assigned to Mitsubishi Engineering-Plastics Corporation. The grantee listed for this patent is Mitsubishi Engineering-Plastics Corporation. Invention is credited to Atsushi Motegi.
United States Patent |
11,168,199 |
Motegi |
November 9, 2021 |
Polycarbonate resin composition
Abstract
Provided is a polycarbonate resin composition that can block
ultraviolet light as well as light on the visible light side
therefrom at wavelengths of 400 to 420 nm, and that is free of the
problem of gas generation during molding. The polycarbonate resin
composition characteristically comprises, per 100 parts by mass of
a polycarbonate resin (A), (i) 0.02 to 1 parts by mass of a sesamol
group-containing benzotriazole ultraviolet absorber (B1) having a
maximum absorption wavelength of at least 375 nm in the absorption
curve determined according to JIS K 7105 using the following
formula, or (ii) 0.08 to 1 parts by mass of a sesamol
group-containing benzotriazole ultraviolet absorber (B2) having a
maximum absorption wavelength of at least 360 nm and less than 375
nm in the absorption curve determined according to JIS K 7105 using
the following formula; and 0.01 to 0.5% by mass of a stabilizer
(C).
Inventors: |
Motegi; Atsushi (Hiratsuka,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Engineering-Plastics Corporation |
Minato-ku |
N/A |
JP |
|
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Assignee: |
Mitsubishi Engineering-Plastics
Corporation (Minato-ku, JP)
|
Family
ID: |
1000005918508 |
Appl.
No.: |
16/339,505 |
Filed: |
September 4, 2017 |
PCT
Filed: |
September 04, 2017 |
PCT No.: |
PCT/JP2017/031780 |
371(c)(1),(2),(4) Date: |
April 04, 2019 |
PCT
Pub. No.: |
WO2018/096758 |
PCT
Pub. Date: |
May 31, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190233616 A1 |
Aug 1, 2019 |
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Foreign Application Priority Data
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Nov 28, 2016 [JP] |
|
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JP2016-230074 |
Nov 28, 2016 [JP] |
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JP2016-230075 |
Jul 25, 2017 [JP] |
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JP2017-143918 |
Jul 25, 2017 [JP] |
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JP2017-143919 |
Aug 16, 2017 [JP] |
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JP2017-157212 |
Aug 16, 2017 [JP] |
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JP2017-157213 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K
5/49 (20130101); C08L 69/00 (20130101); C07D
405/10 (20130101); C08K 5/3475 (20130101); C08G
64/06 (20130101); G02B 1/04 (20130101); G02B
5/208 (20130101); C08L 69/00 (20130101); C08K
5/005 (20130101); C08K 5/3475 (20130101); C08L
69/00 (20130101); C07D 405/04 (20130101); C08K
5/005 (20130101); C08K 2201/014 (20130101); G02B
1/041 (20130101); G02B 1/041 (20130101); C08L
69/00 (20130101) |
Current International
Class: |
C08K
5/3475 (20060101); C08L 69/00 (20060101); G02B
5/20 (20060101); G02B 1/04 (20060101); C08K
5/49 (20060101); C08G 64/06 (20060101); C07D
405/10 (20060101); C07D 405/04 (20060101); C08K
5/00 (20060101) |
Field of
Search: |
;252/589 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 786 675 |
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Jul 1997 |
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EP |
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2 287 655 |
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Feb 2011 |
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EP |
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3 081 965 |
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Oct 2016 |
|
EP |
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6-51840 |
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Jun 1987 |
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JP |
|
0786675 |
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Jan 1997 |
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JP |
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9-263694 |
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Oct 1997 |
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JP |
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9-291205 |
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Nov 1997 |
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JP |
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2001-131399 |
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May 2001 |
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JP |
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2012-25680 |
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Feb 2012 |
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JP |
|
2012025680 |
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Feb 2012 |
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JP |
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2012-41333 |
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Mar 2012 |
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JP |
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201241333 |
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Mar 2012 |
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JP |
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2013-107928 |
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Jun 2013 |
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JP |
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2013-139097 |
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Jul 2013 |
|
JP |
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2014-151540 |
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Aug 2014 |
|
JP |
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2015-189933 |
|
Nov 2015 |
|
JP |
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2015-196694 |
|
Nov 2015 |
|
JP |
|
WO 2005/069061 |
|
Jul 2005 |
|
WO |
|
Other References
International Search Report dated Nov. 21, 2017 in
PCT/JP2017/031780 filed Sep. 4, 2017. cited by applicant .
Office Action dated Aug. 31, 2021, in Japanese Patent Application
No. 2017-157212 (English translation only). cited by
applicant.
|
Primary Examiner: Choi; Ling Siu
Assistant Examiner: Grinsted; Ronald
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
The invention claimed is:
1. A polycarbonate resin composition, comprising: a polycarbonate
resin (A) and, per 100 parts by mass of the polycarbonate resin
(A); from 0.02 to 0.1 parts by mass of a first sesamol
group-comprising benzotriazole ultraviolet absorber (B1) of formula
(1) ##STR00007## X being a halogen atom, and the first ultraviolet
absorber (B1) having a maximum absorption wavelength of at least
375 nm in an absorption curve determined according to JIS K 7105
using formula (x), below; and ##STR00008## from 0.01 to 0.5 parts
by mass of a stabilizer (C), wherein the formula (x) is [an
absorbance of the polycarbonate resin (A) comprising 0.005% by mass
of the first ultraviolet absorber (B1)]-[an absorbance of the
polycarbonate resin (A)].
2. The composition of claim 1, further comprising: from 0.08 to 1
parts by mass of a second sesamol group comprising benzotriazole
ultraviolet absorber (B2), per 100 parts by mass of the
polycarbonate resin (A), having a maximum absorption wavelength of
at least 360 nm and less than 375 nm in the absorption curve
determined according to JIS K 7105 using formula [an absorbance of
the polycarbonate resin (A) comprising 0.005% by mass of the second
ultraviolet absorber (B2)]- [an absorbance of the polycarbonate
resin (A)].
3. The composition of claim 2, wherein the ultraviolet absorber
(B2) has formula (2): ##STR00009## wherein R is a hydrogen atom, an
alkyl group comprising 1 to 8 carbon atoms, an alkoxy group having
1 to 8 carbon atoms, a hydroxyl group, a carboxyl group, an
alkyloxycarbonyl group comprising 1 to 8 carbon atoms in the alkyl
group, a hydroxyalkyl group comprising 1 to 8 carbon atoms, or an
alkylcarbonyloxyalkyl group comprising 1 to 8 carbon atoms in each
of the alkyl groups.
4. The composition of claim 1, further comprising, per 100 parts by
mass of the polycarbonate resin (A): from 0.01 to 0.2 parts by mass
of a third ultraviolet absorber (B3) having a maximum absorption
wavelength of less than 360 nm in an absorption curve determined
according to JIS K 7105 using the following formula [an absorbance
of the polycarbonate resin (A) comprising 0.005% by mass of the
third ultraviolet absorber (B3)]- [an absorbance of the
polycarbonate resin (A)].
5. The composition of claim 4, wherein the third ultraviolet
absorber (B3) is at least one selected from the group consisting of
a benzotriazole ultraviolet absorber lacking a sesamol group, a
triazine ultraviolet absorber, a malonate ester ultraviolet
absorber, and a benzoxazine ultraviolet absorber.
6. The composition of claim 1, wherein a transmittance measured
according to JIS K 7105 at a wavelength of 420 nm on a 2 mm-thick
molded article is not greater than 25%.
7. A molded article, comprising the polycarbonate resin composition
of claim 1.
8. The composition of claim 1, wherein X in the first ultraviolet
absorber (B1) is Cl.
9. The composition of claim 1, wherein X in the first ultraviolet
absorber (B1) is not Cl.
10. The composition of claim 1, wherein X in the first ultraviolet
absorber (B1) is Br.
11. The composition of claim 1, wherein the stabilizer (C)
comprises a phosphorus stabilizer.
12. The composition of claim 1, wherein the stabilizer (C)
comprises a phenolic stabilizer.
13. The composition of claim 1, wherein the stabilizer (C)
comprises a sulfur stabilizer.
14. The composition of claim 1, wherein the stabilizer (C)
comprises a compound of formula (C4) ##STR00010## wherein R.sup.1,
R.sup.2, and R.sup.3 are independently an aryl group comprising 6
to 30 carbon atoms.
15. The composition of claim 1, wherein the stabilizer (C)
comprises a compound of formula (C5) ##STR00011## wherein R.sup.4
and R.sup.5 are independently an aryl group comprising 6 to 30
carbon atoms.
16. The composition of claim 3, wherein R in the ultraviolet
absorber (B2) is not methyl.
17. The composition of claim 1, wherein the stabilizer (C)
comprises a pentaerythritol diphosphite.
18. The composition of claim 1, wherein the stabilizer (C)
comprises a bis(2,4-di-tert-butyl-4-methylphenyl) pentaerythritol
diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol
diphosphite, and/or bis(2,4-dicumylphenyl) pentaerythritol
diphosphite.
19. The composition of claim 1, wherein the stabilizer (C) is
present in a range of from 0.08 to 0.5 parts by mass.
Description
TECHNICAL FIELD
The present invention relates to a polycarbonate resin composition
and more particularly relates to a polycarbonate resin composition
that can block light at wavelengths of 400 to 420 nm on the visible
light side from ultraviolet light, and that is free of the problem
of gas generation during molding.
BACKGROUND ART
The eyes are routinely exposed to damage from sunlight, and it is
thus important to protect the eyes from ultraviolet light, the
wavelength of which extends to 400 nm. In addition, recent research
has shown that the wavelength band on the visible light side from
ultraviolet light can also damage eye tissue and is a cause of, for
example, cataracts. Moreover, as devices and lighting that employ
LEDs as a light source have become more widespread, there have also
been reports that blue light, which is present in large amounts in
LED light sources, is a cause of eye disease.
There is thus demand for materials that block ultraviolet light as
well as light at wavelengths of 400 to 420 nm, which is on the
visible light side therefrom.
Polycarbonate resins generally exhibit excellent mechanical
properties, weathering resistance, and transparency, and
polycarbonate resin compositions that incorporate an ultraviolet
absorber are used as ultraviolet-absorbing transparent materials
for, e.g., eyeglasses, sunglasses, goggles, various lighting
covers, and so forth. For example, benzophenones, benzotriazoles,
triazines, salicylates, and so forth are used as the ultraviolet
absorber (for example, PTL 1 and PTL 2).
However, a practical polycarbonate resin composition that can
effectively absorb and block the 400 to 420 nm wavelengths is not
known.
In addition, when blocking light with a wavelength of 420 nm has
been pursued using conventional ultraviolet absorbers such as those
indicated above, a problem has been that their large levels of
incorporation have ended up causing a large amount of gas
generation during molding.
Resin compositions comprising a polycarbonate resin and such
ultraviolet absorbers are known, but at present a polycarbonate
resin composition that can effectively absorb and block the 400 to
420 nm wavelengths while being free of the problem of gas
generation during molding is not known.
CITATION LIST
Patent Literature
[PTL 1] JP H09-291205 A
[PTL 2] JP H06-51840 B
SUMMARY OF INVENTION
Technical Problem
The present invention was pursued considering the circumstances
described above and has as an object (problem) the provision of a
polycarbonate resin composition that can block ultraviolet light as
well as light on the visible light side therefrom at wavelengths of
400 to 420 nm, and that is free of the problem of gas generation
during molding.
Solution to Problem
As a result of extensive and intensive investigations in order to
address the aforementioned problem, the present inventor discovered
that, through the incorporation, in prescribed amounts in each
case, of an ultraviolet absorber having a prescribed maximum
absorption wavelength and a phosphorus stabilizer, a polycarbonate
resin composition is obtained that can block light at wavelengths
of 400 to 420 nm and that is free of the problem of gas generation
during molding.
The present invention relates to a polycarbonate resin composition
comprising, per 100 parts by mass of a polycarbonate resin (A),
(i) 0.02 to 1 parts by mass of a sesamol group-containing
benzotriazole ultraviolet absorber (B1) having a maximum absorption
wavelength of at least 375 nm in the absorption curve determined
according to JIS K 7105 using the following formula, or
(ii) 0.08 to 1 parts by mass of a sesamol group-containing
benzotriazole ultraviolet absorber (B2) having a maximum absorption
wavelength of at least 360 nm and less than 375 nm in the
absorption curve determined according to JIS K 7105 using the
following formula; and
0.01 to 0.5 parts by mass of a stabilizer (C). [absorbance of the
polycarbonate resin that contains 0.005% by mass of the ultraviolet
absorber]-[absorbance of only the polycarbonate resin]
Advantageous Effects of Invention
The polycarbonate resin composition according to the present
invention can block ultraviolet light as well as light on the
visible light side therefrom at wavelengths of 400 to 420 nm, and
is free of the problem of gas generation during molding.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a plan view of a drop-shaped mold used in the evaluation
of mold contamination in the examples.
DESCRIPTION OF EMBODIMENTS
The present invention is described in detail in the following using
embodiments, examples, and so forth.
Unless specifically indicated otherwise, in this Description "to"
in the specification of a numerical value range is used in the
sense of including the numerical values before and after the "to"
that are used as the lower limit and upper limit.
The present invention is as described above and is constituted of a
first invention, which incorporates (i) 0.02 to 1 parts by mass of
a sesamol group-containing benzotriazole ultraviolet absorber (B1)
having a maximum absorption wavelength of at least 375 nm, and
a second invention, which incorporates (ii) 0.08 to 1 parts by mass
of a sesamol group-containing benzotriazole ultraviolet absorber
(B2) having a maximum absorption wavelength of at least 360 nm and
less than 375 nm in the absorption curve determined according to
JIS K 7105 using the following formula.
The aforementioned first invention is described first hereinbelow,
followed by a description of the aforementioned second
invention.
First Invention
The first invention is described first in the following.
The first invention relates to the polycarbonate resin composition
and molded article described in the following.
[1] A polycarbonate resin composition comprising, per 100 parts by
mass of a polycarbonate resin (A), 0.02 to 1 parts by mass of an
ultraviolet absorber (B1) having a maximum absorption wavelength of
at least 375 nm in the absorption curve determined according to JIS
K 7105 using the following formula, and 0.01 to 0.5 parts by mass
of a stabilizer (C). [absorbance of the polycarbonate resin that
contains 0.005% by mass of the ultraviolet absorber]-[absorbance of
only the polycarbonate resin]
[2] The polycarbonate resin composition according to [1], wherein
the ultraviolet absorber (B1) is a sesamol group-containing
benzotriazole ultraviolet absorber.
[3] The polycarbonate resin composition according to [1] or [2],
wherein the ultraviolet absorber (B1) is an ultraviolet absorber
represented by the following general formula (1).
##STR00001##
(In the formula, X represents a halogen atom.)
[4] The polycarbonate resin composition according to any of [1] to
[3], that further contains, per 100 parts by mass of the
polycarbonate resin (A), at least 0.01 parts by mass and less than
0.08 parts by mass of the sesamol group-containing benzotriazole
ultraviolet absorber (B2) having a maximum absorption wavelength of
at least 360 nm and less than 375 nm in the absorption curve
determined according to JIS K 7105 using the formula given
above.
[5] The polycarbonate resin composition according to any of [1] to
[4], that further contains, per 100 parts by mass of the
polycarbonate resin (A), 0.01 to 0.2 parts by mass of an
ultraviolet absorber (B2) having a maximum absorption wavelength of
less than 360 nm in the absorption curve determined according to
JIS K 7105 using the formula given above.
[6] The polycarbonate resin composition according to [5], wherein
the ultraviolet absorber (B2) is at least one selection from
benzotriazole ultraviolet absorbers lacking sesamol group, triazine
ultraviolet absorbers, malonate ester ultraviolet absorbers, and
benzoxazine ultraviolet absorbers.
[7] The polycarbonate resin composition according to any of [1] to
[6], wherein the transmittance measured according to JIS K 7105 at
a wavelength of 420 nm on a 2 mm-thick molded article is not
greater than 25%.
[8] A molded article of the polycarbonate resin composition
according to any of [1] to [7].
The components and so forth constituting the polycarbonate resin
composition of the first invention are described in detail in the
following.
[Polycarbonate Resin (A)]
The polycarbonate resin is a polymer with a basic structure that
has the carbonate bond given by the formula
--[--O--X--O--C(.dbd.O)--]--. X in the formula is generally a
hydrocarbon, but an X incorporating a heteroatom or hetero bond may
be used in order to impart various properties.
Polycarbonate resins can be classified into aromatic polycarbonate
resins, in which each of the carbon atoms directly bonded to the
carbonate bond is an aromatic carbon, and aliphatic polycarbonate
resins, in which they are aliphatic carbon atoms, and either of
these can be used. Aromatic polycarbonate resins are preferred
therebetween considering, for example, the heat resistance,
mechanical properties, and electrical properties.
There are no limitations on the specific species of polycarbonate
resin, and examples here are polycarbonate polymers provided by the
reaction of a dihydroxy compound with a carbonate precursor. A
polyhydroxy compound and so forth may also be reacted here in
addition to the dihydroxy compound and carbonate precursor. A
method may also be used in which carbon dioxide is reacted as the
carbonate precursor with a cyclic ether. The polycarbonate polymer
may be a linear or branched chain. In addition, the polycarbonate
polymer may be a homopolymer composed of a single species of repeat
unit or may be a copolymer having two or more species of repeat
units. Various copolymerization modes may be selected for such a
copolymer, e.g., random copolymer, block copolymer, and so forth. A
polycarbonate polymer as described here is generally a
thermoplastic resin.
Among the monomers comprising the starting materials for aromatic
polycarbonate resins, aromatic dihydroxy compounds can be
exemplified by the following:
dihydroxybenzenes, e.g., 1,2-dihydroxybenzene, 1,3-dihydroxybenzene
(i.e., resorcinol), and 1,4-dihydroxybenzene;
dihydroxybiphenyls, e.g., 2,5-dihydroxybiphenyl,
2,2'-dihydroxybiphenyl, and 4,4'-dihydroxybiphenyl;
dihydroxynaphthalenes, e.g., 2,2'-dihydroxy-1,1'-binaphthyl,
1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene,
2,3-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,
2,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and
2,7-dihydroxynaphthalene;
dihydroxydiaryl ethers such as 2,2'-dihydroxydiphenyl ether,
3,3'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ether,
4,4'-dihydroxy-3,3'-dimethyldiphenyl ether,
1,4-bis(3-hydroxyphenoxy)benzene, and 1,3-bis(4-hydroxyphenoxy)
benzene;
bis(hydroxyaryl)alkanes such as 2,2-bis(4-hydroxyphenyl)propane
(i.e., bisphenol A), 1,1-bis(4-hydroxyphenyl)propane,
2,2-bis(3-methyl-4-hydroxyphenyl)propane,
2,2-bis(3-methoxy-4-hydroxyphenyl)propane,
2-(4-hydroxyphenyl)-2-(3-methoxy-4-hydroxyphenyl)propane,
1,1-bis(3-tert-butyl-4-hydroxyphenyl)propane,
2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane,
2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,
2-(4-hydroxyphenyl)-2-(3-cyclohexyl-4-hydroxyphenyl)propane,
.alpha.,.alpha.'-bis(4-hydroxyphenyl)-1,4-diisopropylbenzene,
1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene,
bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)cyclohexylmethane,
bis(4-hydroxyphenyl)phenylmethane,
bis(4-hydroxyphenyl)(4-propenylphenyl)methane,
bis(4-hydroxyphenyl)diphenylmethane,
bis(4-hydroxyphenyl)naphthylmethane,
1,1-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
1,1-bis(4-hydroxyphenyl)-1-naphthylethane,
1,1-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane,
2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)hexane,
2,2-bis(4-hydroxyphenyl)hexane, 1,1-bis(4-hydroxyphenyl)octane,
2,2-bis(4-hydroxyphenyl)octane, 4,4-bis(4-hydroxyphenyl)heptane,
2,2-bis(4-hydroxyphenyl)nonane, 1,1-bis(4-hydroxyphenyl)decane, and
1,1-bis(4-hydroxyphenyl)dodecane;
bis(hydroxyaryl)cycloalkanes such as
1,1-bis(4-hydroxyphenyl)cyclopentane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,4-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,5-dimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3-propyl-5-methylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3-tert-butylcyclohexane,
1,1-bis(4-hydroxyphenyl)-4-tert-butylcyclohexane,
1,1-bis(4-hydroxyphenyl)-3-phenylcyclohexane, and
1,1-bis(4-hydroxyphenyl)-4-phenylcyclohexane;
cardo structure-containing bisphenols such as
9,9-bis(4-hydroxyphenyl)fluorene and
9,9-bis(4-hydroxy-3-methylphenyl)fluorene;
dihydroxydiaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide and
4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide;
dihydroxydiaryl sulfoxides such as 4,4'-dihydroxydiphenyl sulfoxide
and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide; and
dihydroxydiaryl sulfones such as 4,4'-dihydroxydiphenyl sulfone and
4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone.
Among the preceding, the bis(hydroxyaryl)alkanes are preferred and
among them the bis(4-hydroxyphenyl)alkanes are preferred, while
2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A) is particularly
preferred from the standpoints of the impact resistance and heat
resistance.
A single aromatic dihydroxy compound may be used or any combination
of two or more in any proportions may be used.
The monomers comprising the starting materials for aliphatic
polycarbonate resins can be exemplified by the following:
alkanediols such as ethane-1,2-diol, propane-1,2-diol,
propane-1,3-diol, 2,2-dimethylpropane-1,3-diol,
2-methyl-2-propylpropane-1,3-diol, butane-1,4-diol,
pentane-1,5-diol, hexane-1,6-diol, and decane-1,10-diol;
cycloalkanediols such as cyclopentane-1,2-diol,
cyclohexane-1,2-diol, cyclohexane-1,4-diol,
1,4-cyclohexanedimethanol, 4-(2-hydroxyethyl)cyclohexanol, and
2,2,4,4-tetramethylcyclobutane-1,3-diol;
glycols such as ethylene glycol, 2,2'-oxydiethanol (i.e.,
diethylene glycol), triethylene glycol, propylene glycol, and
spiroglycol;
aralkyl diols such as 1,2-benzenedimethanol, 1,3-benzenedimethanol,
1,4-benzenedimethanol, 1,4-benzenediethanol,
1,3-bis(2-hydroxyethoxy)benzene, 1,4-bis(2-hydroxyethoxy)benzene,
2,3-bis(hydroxymethyl)naphthalene,
1,6-bis(hydroxyethoxy)naphthalene, 4,4'-biphenyldimethanol,
4,4'-biphenyldiethanol, 1,4-bis(2-hydroxyethoxy)biphenyl, bisphenol
A bis(2-hydroxyethyl) ether, and bisphenol S bis(2-hydroxyethyl)
ether; and
cyclic ethers such as 1,2-epoxyethane (i.e., ethylene oxide),
1,2-epoxypropane (i.e., propylene oxide), 1,2-epoxycyclopentane,
1,2-epoxycyclohexane, 1,4-epoxycyclohexane,
1-methyl-1,2-epoxycyclohexane, 2,3-epoxynorbornane, and
1,3-epoxypropane.
Of the monomers comprising the starting materials for polycarbonate
resins, the carbonate precursor can be exemplified by carbonyl
halides and carbonate esters. A single carbonate precursor may be
used or any combination of two or more in any proportions may be
used.
The carbonyl halides can be specifically exemplified by phosgene
and by haloformates such as the bischloroformates of dihydroxy
compounds and the monochloroformates of dihydroxy compounds.
The carbonate esters can be specifically exemplified by diaryl
carbonates such as diphenyl carbonate and ditolyl carbonate;
dialkyl carbonates such as dimethyl carbonate and diethyl
carbonate; and carbonates of dihydroxy compounds, e.g.,
biscarbonates of dihydroxy compounds, monocarbonates of dihydroxy
compounds, and cyclic carbonates.
There are no particular limitations on the method of producing the
polycarbonate resin, and any method can be used. Examples thereof
are the interfacial polymerization method, melt transesterification
method, pyridine method, ring-opening polymerization of a cyclic
carbonate compound, and solid-state transesterification of a
prepolymer.
The molecular weight of the polycarbonate resin (A), expressed as
the viscosity-average molecular weight (Mv), is preferably in the
range from 16,000 to 50,000 and is more preferably at least 18,000
and still more preferably at least 20,000 and is more preferably
not more than 45,000, still more preferably not more than 40,000,
and particularly preferably not more than 38,000. A
viscosity-average molecular weight of less than 16,000 facilitates
a decline in the impact resistance of the molded article and
creates a cracking risk and is thus disfavored. A viscosity-average
molecular weight of greater than 50,000 results in a poor
flowability and facilitates the appearance of problems with the
moldability and is thus also disfavored.
A mixture of two or more polycarbonate resins having different
viscosity-average molecular weights may be used for the
polycarbonate resin (A), in which case a polycarbonate resin having
a viscosity-average molecular weight outside the aforementioned
preferred range may be admixed.
In the present invention, the viscosity-average molecular weight
[Mv] of the polycarbonate resin refers to the value calculated
using Schnell's viscosity equation, i.e.,
.eta.=1.23.times.10.sup.-4Mv.sup.0.83, wherein the intrinsic
viscosity [.eta.] (unit: dl/g) is determined at a temperature of
20.degree. C. using methylene chloride as the solvent and using a
Ubbelohde viscometer. The intrinsic viscosity [.eta.] is the value
calculated using the following formula and the specific viscosity
[.eta..sub.sp] measured at each solution concentration [C]
(g/dl).
.eta.>.times..times..eta..times. ##EQU00001##
In addition, a combination of polycarbonate resin with another
thermoplastic resin may be used in the present invention. Moreover,
it may be structured as a copolymer in which polycarbonate resin is
the major portion, for example, as a copolymer of a polycarbonate
resin with a siloxane structure-containing oligomer or polymer,
with the goal of raising the flame retardancy and impact resistance
still further; as a copolymer of a polycarbonate resin with a
phosphorus atom-containing monomer, oligomer, or polymer, with the
goal of raising the thermal oxidation stability and flame
retardancy still further; as a copolymer of a polycarbonate resin
with a dihydroxyanthraquinone structure-containing monomer,
oligomer, or polymer, with the goal of improving the thermal
oxidation stability; as a copolymer of a polycarbonate resin with
an oligomer or polymer having an olefinic structure, e.g.,
polystyrene, in order to improve the optical properties; or as a
copolymer of a polycarbonate resin with a polyester resin oligomer
or polymer with the goal of enhancing the chemical resistance.
In addition, the polycarbonate resin may contain a polycarbonate
oligomer in order to bring about an improved appearance for the
molded article and improve the flowability. The viscosity-average
molecular weight (Mv) of this polycarbonate oligomer is generally
at least 1,500 and is preferably at least 2,000 and is generally
not more than 9,500 and is preferably not more than 9,000. The
incorporated polycarbonate oligomer is preferably not more than 30%
by mass of the polycarbonate resin (including the polycarbonate
oligomer).
The polycarbonate resin may be a virgin starting material, but may
also be a polycarbonate resin that has been regenerated from
post-consumer products (also known as material recycled
polycarbonate resin).
However, regenerated polycarbonate resin preferably is not more
than 80% by mass and more preferably not more than 50% by mass of
the polycarbonate resin. Since regenerated polycarbonate resin has
a high potential for deterioration, e.g., thermal deterioration,
ageing deterioration, and so forth, the use of such a polycarbonate
resin in amounts larger than the indicated range creates the
possibility of causing a decline in the color and mechanical
properties.
[Ultraviolet Absorber (B1)]
The polycarbonate resin composition according to the first
invention contains an ultraviolet absorber (B1) for which the
maximum absorption wavelength determined according to JIS K 7105
using the following formula (1) is at least 375 nm. [absorbance of
the polycarbonate resin that contains 0.005% by mass of the
ultraviolet absorber]-[absorbance of only the polycarbonate resin]
(1)
The maximum absorption wavelength of the ultraviolet absorber (B1)
is defined in the present invention as the maximum absorption
wavelength in the absorption curve obtained in accordance with
formula (1) by subtracting, from the absorbance of a flat
plate-shaped molded article of the polycarbonate resin containing
0.005% by mass of the ultraviolet absorber, the absorbance of a
flat plate-shaped molded article with the same shape and same
thickness of the same polycarbonate resin not containing the
ultraviolet absorber. It is thought that in principle the thusly
defined maximum absorption wavelength will not vary as a function
of the thickness of the flat plate-shaped test specimen used, but
the comparison is preferably carried out in the present invention
at a thickness of 2 mm.
The same definition also applies to the maximum absorption
wavelength for the ultraviolet absorbers (B2) and (B3) described
below.
The specific conditions in the method for measuring and determining
the maximum absorption wavelength are as described in the
examples.
While the maximum absorption wavelength of the ultraviolet absorber
(B1) is at least 375 nm, the upper limit parts by mass, the
transmittance of the resulting resin composition in the 400 to 420
nm wavelength region is then too high. When this content exceeds 1
parts by mass, the transmittance in the 400 to 420 nm wavelength
region is low, but gas generation during molding becomes
substantial and the volatile fraction adheres to the molded article
and the appearance of the product is then substantially impaired.
The content of the ultraviolet absorber (B1) per 100 parts by mass
of the polycarbonate resin (A) is preferably at least 0.025 parts
by mass and not more than 0.8 parts by mass, more preferably not
more than 0.7 parts by mass, and still more preferably not more
than 0.6 parts by mass.
[Ultraviolet Absorber (B2)]
The polycarbonate resin composition according to the present
invention preferably additionally contains a sesamol
group-containing benzotriazole ultraviolet absorber (B2) having a
maximum absorption wavelength of at least 360 nm and less than 375
nm in the absorption curve determined according to JIS K 7105 from
formula (1).
The incorporation of the ultraviolet absorber (B2) makes it
possible to ameliorate the trend wherein the transmittance around
320 nm is prone to increase when the content of the ultraviolet
absorber (B1) is relatively small.
The ultraviolet absorber represented by the following general
formula (2) is preferred for the sesamol group-containing
benzotriazole ultraviolet absorber (B2) on this maximum absorption
wavelength is preferably not more than 420 nm and is more
preferably not more than 400 nm.
While this ultraviolet absorber (B1) may be selected from, for
example, benzotriazole compounds, benzophenone compounds, triazine
compounds, benzoate compounds, phenyl salicylate ester compounds,
cyanoacrylate compounds, malonate ester compounds, and oxalic acid
anilides that in each case have a maximum absorption wavelength of
at least 375 nm, benzotriazole ultraviolet absorbers are preferred,
sesamol group (the benzo[1,3]dioxol-5-ol group)-containing
benzotriazole ultraviolet absorbers are more preferred, and the
ultraviolet absorber represented by the following general formula
(1) is particularly preferred.
##STR00002##
The X in general formula (1) is a halogen atom and preferably is a
halogen atom such as chlorine, bromine, fluorine, or iodine and is
more preferably a chlorine atom, and
6-(5-chloro-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol is thus
specifically preferred.
The content of the ultraviolet absorber (B1) is 0.02 to 1 parts by
mass per 100 parts by mass of the polycarbonate resin (A). When
this content is less than 0.02 having a maximum absorption
wavelength of at least 360 nm and less than 375 nm in the
absorption curve determined according to JIS K 7105 from formula
(1).
##STR00003##
(In general formula (2), R represents a hydrogen atom, alkyl group
having 1 to 8 carbon atoms, alkoxy group having 1 to 8 carbon
atoms, hydroxyl group, carboxyl group, alkyloxycarbonyl group
having 1 to 8 carbon atoms in the alkyl group, hydroxyalkyl group
having 1 to 8 carbon atoms, or alkylcarbonyloxyalkyl group having 1
to 8 carbon atoms in each of the alkyl groups.)
The R in general formula (2) can be specifically exemplified by the
following: a hydrogen atom; optionally substituted linear or
branched alkyl groups having 1 to 8 carbon atoms, e.g., methyl
group, ethyl group, propyl group, isopropyl group, n-butyl group,
isobutyl group, sec-butyl group, tert-butyl group, n-hexyl group,
n-octyl group, and 2-ethylhexyl group; optionally substituted
linear or branched alkoxy groups having 1 to 8 carbon atoms, e.g.,
methoxy group, ethoxy group, propoxy group, isopropoxy group,
n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy
group, n-hexyloxy group, n-octyloxy group, and 2-ethylhexyloxy
group; hydroxyl group; carboxyl group; optionally substituted
linear or branched alkyloxycarbonyl groups having 1 to 8 carbon
atoms in the alkyl group, e.g., methoxycarbonyl group,
ethoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl
group, isobutyoxycarbonyl group, sec-butoxycarbonyl group,
tert-butoxycarbonyl group, n-hexyloxycarbonyl group,
n-octyloxycarbonyl group, and 2-ethylhexyloxycarbonyl group;
optionally substituted linear or branched hydroxyalkyl groups
having 1 to 8 carbon atoms, e.g., hydroxymethyl group, hydroxyethyl
group, hydroxypropyl group, hydroxybutyl group, hydroxyhexyl group,
and hydroxyoctyl group; and optionally substituted linear or
branched alkylcarbonyloxyalkyl groups in which each alkyl has 1 to
8 carbon atoms, e.g., methylcarbonyloxymethyl group,
ethylcarbonyloxymethyl group, propylcarbonyloxymethyl group,
butylcarbonyloxymethyl group, hexylcarbonyloxymethyl group,
heptylcarbonyloxymethyl group, octylcarbonyloxymethyl group,
methylcarbonyloxyethyl group, ethylcarbonyloxyethyl group,
propylcarbonyloxyethyl group, butylcarbonyloxyethyl group,
hexylcarbonyloxyethyl group, heptylcarbonyloxyethyl group, and
octylcarbonyloxyethyl group.
Preferred among the preceding for R are the hydrogen atom, alkyl
groups, alkoxy groups, hydroxyl group, carboxyl group,
alkyloxycarbonyl groups, hydroxyalkyl groups, and
alkylcarbonyloxyalkyl groups. More preferred are hydrogen atom,
methyl group, methoxy group, n-octyloxy group, hydroxyl group,
carboxyl group, methoxycarbonyl group, n-octyloxycarbonyl group,
hydroxyethyl group, methylcarbonyloxyethyl group, and
heptylcarbonyloxyethyl group.
The following are preferred examples of compounds represented by
general formula (2) and having a maximum absorption wavelength of
at least 360 nm and less than 375 nm:
6-(2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-n-heptylcarbonyloxyethyl
-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-isoheptylcarbonyloxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol-
, 6-(5-methyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-methoxy-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-hydroxy-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-octyloxy-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-carboxy-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-hydroxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol, and
6-(5-methylcarbonyloxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol.
Particularly preferred among the preceding are
6-(2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol,
6-(5-n-heptylcarbonyloxyethyl
-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol, and
6-(5-isoheptylcarbonyloxyethyl-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol-
.
The preferred content of the ultraviolet absorber (B2) is from at
least 0.01 parts by mass to less than 0.08 parts by mass per 100
parts by mass of the polycarbonate resin (A). Transmission around
the 320 nm wavelength by the resulting resin composition readily
occurs at less than 0.01 parts by mass. While at and above 0.08
parts by mass, the occurrence of gas generation during molding is
facilitated and the product appearance is readily impaired. The
content of the ultraviolet absorber (B2) per 100 parts by mass of
the polycarbonate resin (A) is more preferably at least 0.02 parts
by mass and still more preferably at least 0.03 parts by mass and
is more preferably not more than 0.07 parts by mass, still more
preferably not more than 0.05 parts by mass, and particularly
preferably not more than 0.04 parts by mass.
[Ultraviolet Absorber (B3)]
The polycarbonate resin composition according to the first
invention preferably additionally contains (B3) an ultraviolet
absorber having a maximum absorption wavelength of less than 360 nm
in the absorption curve determined according to JIS K 7105 from
formula (1).
The incorporation of the ultraviolet absorber (B3) makes it
possible to ameliorate the trend wherein the transmittance around
320 nm is prone to increase when the content of the ultraviolet
absorber (B1) is relatively small.
The ultraviolet absorber (B3) can be exemplified by benzotriazole
compounds, benzophenone compounds, triazine compounds, benzoxazine
compounds, benzoate compounds, phenyl salicylate ester compounds,
cyanoacrylate compounds, malonate ester compounds, and oxalic acid
anilides. Preferred among the preceding are benzotriazole
compounds, triazine compounds, malonate ester compounds, and
benzoxazine compounds. A single one of these may be used or two or
more may be used.
The hydroxybenzophenone compounds can be exemplified by
2-hydroxy-4-octoxybenzophenone.
The malonate ester compounds can be exemplified by dimethyl
(p-methoxybenzylidene)malonate, 2-(1-arylalkylidene)malonate
esters, and tetraethyl
2,2'-(1,4-phenylenedimethylidene)bismalonate.
The triazine compounds can be exemplified by
2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol.
The benzoate compounds can be exemplified by
2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate.
The benzoxazine compounds can be exemplified by
2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one).
The ultraviolet absorber (B3) is more preferably a benzotriazole
ultraviolet absorber and is particularly preferably a benzotriazole
compound that does not have a sesamol group. The following are
preferred specific examples of such benzotriazole compounds:
2-(2-hydroxy-5-t-octylphenyl) -2H-benzotriazole,
2-(3-t-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H-benzotriazole,
2-[5-chloro(2H)-benzotriazol -2-yl]-4-methyl-6-(t-butyl)phenol,
2,4-di-tert-butyl -6-(5-chlorobenzotriazol-2-yl)phenol,
(2-[5-chloro(2H)-benzotriazol -2-yl]-4,6-di(tert-pentyl)phenol),
3-[3-tert-butyl
-5-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]octyl
propionate,
2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole,
2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol,
2-(2H-benztotriazol-2-yl)-p-cresol, 2-[(2H)-benzotriazol
-2-yl]-4,6-bis(1-methyl-1-phenylethyl)phenol.
The preferred content of the ultraviolet absorber (B3) is 0.01 to
0.2 parts by mass per 100 parts by mass of the polycarbonate resin
(A). Transmission around the 320 nm wavelength by the resulting
resin composition readily occurs at less than 0.01 parts by mass.
While at above 0.2 parts by mass, the occurrence of gas generation
during molding is facilitated and the product appearance is readily
impaired. The content of the ultraviolet absorber (B3) per 100
parts by mass of the polycarbonate resin (A) is more preferably at
least 0.02 parts by mass and still more preferably at least 0.03
parts by mass and is more preferably not more than 0.15 parts by
mass.
[Stabilizer (C)]
The polycarbonate resin composition according to the first
invention contains a stabilizer (C). This stabilizer (C) is
exemplified by phosphorus stabilizers, phenolic stabilizers, sulfur
stabilizers, and so forth. The polycarbonate resin composition
according to the second invention also contains a stabilizer (C),
and its type, content, and so forth are the same as for the first
invention. The description that follows also applies to the
stabilizer (C) in the second invention.
[Phosphorus Stabilizer]
Through the incorporation of a phosphorus stabilizer in the
polycarbonate resin composition according to the present invention,
the polycarbonate resin composition assumes a good color and
exhibits additional improvements in its resistance to thermal
discoloration.
Any known phosphorus stabilizer can be used as the phosphorus
stabilizer here. Specific examples are the oxo acids of phosphorus,
e.g., phosphoric acid, phosphonic acid, phosphorous acid,
phosphinic acid, and polyphosphoric acid; acidic pyrophosphate
metal salts, e.g., sodium acidic pyrophosphate, potassium acidic
pyrophosphate, and calcium acidic pyrophosphate; salts of
phosphoric acid with a Group 1 or Group 2B metal, e.g., potassium
phosphate, sodium phosphate, cesium phosphate, and zinc phosphate;
phosphate compounds; phosphite compounds; and phosphonite
compounds, with phosphite compounds being particularly preferred.
By selecting a phosphite compound, a polycarbonate resin
composition can be obtained that exhibits a higher resistance to
discoloration and a better continuous production capability.
This phosphite compound is a trivalent phosphorus compound
represented by the general formula P(OR).sub.3 where R represents a
monovalent or divalent organic group.
This phosphite compound is exemplified by triphenyl phosphite,
tris(monononylphenyl) phosphite, tris(monononyl/dinonyl-phenyl)
phosphite, tris(2,4-di-tert-butylphenyl) phosphite, monooctyl
diphenyl phosphite, dioctyl monophenyl phosphite, monodecyl
diphenyl phosphite, didecyl monophenyl phosphite, tridecyl
phosphite, trilauryl phosphite, tristearyl phosphite, distearyl
pentaerythritol diphosphite, bis(2,4-di-tert-butyl-4-methylphenyl)
pentaerythritol phosphite, bis(2,6-di-tert-butylphenyl) octyl
phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl) octyl
phosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene
diphosphite, and
6-[3-(3-tert-butyl-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-bu-
tyldibenzo[d,f][1,3,2]dioxaphosphepine.
Among these phosphite compounds, the aromatic phosphite compounds
represented by the following general formulas (3) and (4) are more
preferred because they effectively increase the resistance to
thermal discoloration exhibited by the polycarbonate resin
composition according to the present invention.
##STR00004##
(In the formula, R.sup.1, R.sup.2, and R.sup.3 each independently
represent an aryl group having 6 to 30 carbon atoms.)
##STR00005##
(In the formula, R.sup.4 and R.sup.5 each independently represent
an aryl group having 6 to 30 carbon atoms.)
Among the phosphite compounds represented by formula (3), triphenyl
phosphite, tris(monononylphenyl) phosphite,
tris(2,4-di-tert-butylphenyl) phosphite, and so forth are preferred
whereamong tris(2,4-di-tert-butylphenyl) phosphite is more
preferred.
Among the phosphite compounds represented by formula (4), those
having a pentaerythritol diphosphite structure, such as
bis(2,4-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite,
bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite,
and bis(2,4-dicumylphenyl) pentaerythritol diphosphite, are
particularly preferred.
Among the phosphite compounds, aromatic phosphite compounds with
formula (4) provide an even better color and are thus more
preferred.
A single phosphorus stabilizer may be incorporated or any
combination of two or more phosphorus stabilizers in any
proportions may be incorporated.
The content of the phosphorus stabilizer, per 100 parts by mass of
the polycarbonate resin (A), is 0.01 to 0.5 parts by mass and
preferably at least 0.02 parts by mass and more preferably at least
0.03 parts by mass, and is preferably not more than 0.4 parts by
mass, more preferably not more than 0.3 parts by mass, and still
more preferably not more than 0.2 parts by mass. The color and
thermal discoloration resistance are unsatisfactory when the
phosphorus stabilizer content is less than 0.005 parts by mass. At
above 0.5 parts by mass, the thermal discoloration resistance
actually deteriorates instead and the moist heat stability declines
as well.
[Phenolic Stabilizer]
The polycarbonate resin composition according to the present
invention may contain a phenolic stabilizer as the stabilizer.
Hindered phenolic oxidation inhibitors are examples of phenolic
stabilizers. Specific examples thereof are pentaerythritol
tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],
octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,
thiodiethylenebis[3-(3,5-di-tert-butyl
-4-hydroxyphenyl)propionate],
N,N'-hexan-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide]-
, 2,4-dimethyl -6-(1-methylpentadecyl)phenol, diethyl
[[3,5-bis(1,1-dimethylethyl) -4-hydroxyphenyl]methyl]phosphoate,
3,3',3'',5,5',5''-hexa-tert-butyl-.alpha.,.alpha.',.alpha.''-(mesitylen-2-
,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol,
ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate]-
,
hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],
1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)
-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert
-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, and
2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl
acrylate.
Pentaerythritol
tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and
octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are
preferred among the preceding. These phenolic oxidation inhibitors
can be specifically exemplified by "Irganox 1010" and "Irganox
1076" from BASF and "ADK STAB AO-50" and "ADK STAB AO-60" from the
ADEKA Corporation.
A single phenolic stabilizer may be incorporated or any combination
of two or more in any proportions may be incorporated.
The content of the phenolic stabilizer, per 100 parts by mass of
the polycarbonate resin (A), is 0.01 to 0.5 parts by mass and is
preferably at least 0.02 parts by mass and more preferably at least
0.03 parts by mass and is preferably not more than 0.4 parts by
mass, more preferably not more than 0.3 parts by mass, and still
more preferably not more than 0.2 parts by mass. The effect as a
phenolic stabilizer may be unsatisfactory when the phenolic
stabilizer content is less than the lower limit for the indicated
range. When the phenolic stabilizer content exceeds the upper limit
for the indicated range, the effect hits a ceiling and this may
thus be uneconomical.
A phosphorus stabilizer may be used in combination with a phenolic
stabilizer. In such an instance, the total content of the
phosphorus stabilizer and phenolic stabilizer, per 100 parts by
mass of the polycarbonate resin (A), is 0.01 to 0.5 parts by mass
and is preferably at least 0.02 parts by mass and more preferably
at least 0.03 parts by mass and is preferably not more than 0.4
parts by mass, more preferably not more than 0.3 parts by mass, and
still more preferably not more than 0.2 parts by mass.
[Sulfur Stabilizer]
The sulfur stabilizer can be exemplified by dilauryl
3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, dimyristyl
3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, lauryl
stearyl 3,3'-thiodipropionate, pentaerythritol
tetrakis(3-laurylthiopropionate), bis[2-methyl
-4-(3-laurylthiopropionyloxy)-5-tert-butylphenyl] sulfide,
octadecyl disulfide, mercaptobenzimidazole, 2-mercapto
-6-methylbenzimidazole, and 1,1'-thiobis(2-naphthol).
Pentaerythritol tetrakis(3-laurylthiopropionate) is preferred among
the preceding. This sulfur stabilizer can be specifically
exemplified by "ADK STAB AO-412S" from the ADEKA Corporation.
The content of the sulfur stabilizer, per 100 parts by mass of the
polycarbonate resin (A), is 0.01 to 0.5 parts by mass and is
preferably at least 0.02 parts by mass and more preferably at least
0.03 parts by mass and is preferably not more than 0.4 parts by
mass, more preferably not more than 0.3 parts by mass, and still
more preferably not more than 0.2 parts by mass. The effect as a
sulfur stabilizer may be unsatisfactory when the sulfur stabilizer
content is less than the lower limit for the indicated range. When
the sulfur stabilizer content exceeds the upper limit for the
indicated range, the effect hits a ceiling and this may thus be
uneconomical.
[Additives]
The polycarbonate resin composition according to the first
invention may contain additives other than those described above,
for example, additives such as mold-release agents, fluorescent
brighteners, pigments, dyes, flame retardants, impact resistance
enhancers, antistatic agents, plasticizers, compatibilizers, and so
forth, and may contain a polymer other than a polycarbonate resin.
A single one of these additives or two or more of these additives
may be incorporated, while a single additional resin or two or more
additional resins may be incorporated. The polycarbonate resin
composition according to the second invention may also contain
additives other than those described above, and their type,
content, and so forth are the same as for the first invention.
Second Invention
The second invention is described in the following.
The second invention relates to the polycarbonate resin composition
and molded article described in the following.
[1] A polycarbonate resin composition comprising, per 100 parts by
mass of a polycarbonate resin (A), 0.08 to 1 parts by mass of an
ultraviolet absorber (B2) having a maximum absorption wavelength of
at least 360 nm and less than 375 nm in the absorption curve
determined according to JIS K 7105 using the following formula, and
0.01 to 0.5 parts by mass of a stabilizer (C). [absorbance of the
polycarbonate resin that contains 0.005% by mass of the ultraviolet
absorber]-[absorbance of only the polycarbonate resin]
[2] The polycarbonate resin composition according to [1], wherein
the ultraviolet absorber (B2) is a sesamol group-containing
benzotriazole ultraviolet absorber.
[3] The polycarbonate resin composition according to [1] or [2],
wherein the ultraviolet absorber (B2) is an ultraviolet absorber
represented by the following general formula (2).
##STR00006##
(In the formula, R represents a hydrogen atom, alkyl group having 1
to 8 carbon atoms, alkoxy group having 1 to 8 carbon atoms,
hydroxyl group, carboxyl group, alkyloxycarbonyl group having 1 to
8 carbon atoms in the alkyl group, hydroxyalkyl group having 1 to 8
carbon atoms, or alkylcarbonyloxyalkyl group having 1 to 8 carbon
atoms in each of the alkyl groups.)
[4] The polycarbonate resin composition according to any of [1] to
[3], that additionally contains, per 100 parts by mass of the
polycarbonate resin (A), 0.01 to 0.2 parts by mass of (B3) an
ultraviolet absorber having a maximum absorption wavelength of less
than 360 nm in the absorption curve determined according to JIS K
7105 using the following formula.
[5] The polycarbonate resin composition according to [4], wherein
the ultraviolet absorber (B3) is at least one selection from
benzotriazole ultraviolet absorbers lacking sesamol group, triazine
ultraviolet absorbers, malonate ester ultraviolet absorbers, and
benzoxazine ultraviolet absorbers.
[6] The polycarbonate resin composition according to any of [1] to
[5], wherein the transmittance measured according to JIS K 7105 at
a wavelength of 420 nm on a 2 mm-thick molded article is not
greater than 25%.
[7] A molded article of the polycarbonate resin composition
according to any one of [1] to [6].
The individual components themselves used in the polycarbonate
resin composition according to the second invention are
substantially the same components as those described for the first
invention of the present invention, and, unless specifically
indicated otherwise, the description for the first invention as
provided above directly applies to the individual components per se
used in the second invention.
[Polycarbonate Resin (A)]
The polycarbonate resin (A) is as has been described above, and the
same description is also applied to the polycarbonate resin (A)
according to the second invention.
[Ultraviolet Absorber (B2)]
The polycarbonate resin composition according to the second
invention contains an ultraviolet absorber (B2) having a maximum
absorption wavelength of at least 360 nm and less than 375 nm in
the absorption curve determined according to JIS K 7105 using the
following formula (1). [absorbance of the polycarbonate resin that
contains 0.005% by mass of the ultraviolet absorber]-[absorbance of
only the polycarbonate resin] (1)
The ultraviolet absorber (B2) is as has been described above, and
the same description is also applied to the ultraviolet absorber
(B2) according to the second invention.
The content of the ultraviolet absorber (B2) is 0.08 to 1 parts by
mass per 100 parts by mass of the polycarbonate resin (A). When
this content is less than 0.08 parts by mass, the transmittance of
the resulting resin composition in the 400 to 420 nm wavelength
region is then too high. When this content exceeds 1 parts by mass,
the transmittance in the 400 to 420 nm wavelength region is low,
but gas generation during molding becomes substantial and the
volatile fraction adheres to the molded article and the appearance
of the product is then substantially impaired. The content of the
ultraviolet absorber (B2) per 100 parts by mass of the
polycarbonate resin (A) is preferably 0.08 to 0.9 parts by mass,
more preferably 0.08 to 0.8 parts by mass, still more preferably
0.08 to 0.7 parts by mass, and particularly preferably 0.08 to 0.6
parts by mass.
[Ultraviolet Absorber (B3)]
The polycarbonate resin composition according to the second
invention preferably additionally contains (B3) an ultraviolet
absorber having a maximum absorption wavelength of less than 360 nm
in the absorption curve determined according to JIS K 7105 from
formula (1).
The incorporation of the ultraviolet absorber (B3) makes it
possible to ameliorate the trend wherein the transmittance around
320 nm is prone to increase when the content of the ultraviolet
absorber (B2) is relatively small.
With regard to this ultraviolet absorber (B3), the description of
the ultraviolet absorber (B3) for the first invention is also
likewise applied to the ultraviolet absorber (B3) for the second
invention.
The preferred content of the ultraviolet absorber (B3) is from 0.01
to 0.2 parts by mass per 100 parts by mass of the polycarbonate
resin (A). Transmission around the 320 nm wavelength by the
resulting resin composition readily occurs at less than 0.01 parts
by mass, while at above 0.2 parts by mass the occurrence of gas
generation during molding is facilitated and the product appearance
is readily impaired. The content of the ultraviolet absorber (B3)
per 100 parts by mass of the polycarbonate resin (A) is more
preferably at least 0.02 parts by mass and still more preferably at
least 0.03 parts by mass and is more preferably not more than 0.15
parts by mass.
[Stabilizer (C)]
The polycarbonate resin composition according to the second
invention contains a stabilizer (C). This stabilizer (C) can be
exemplified by phosphorus stabilizers, phenolic stabilizers, sulfur
stabilizers, and so forth.
The stabilizer (C) used in the second invention is the same as in
the first invention with regard to type, content, and so forth, and
the previous description likewise applies to the stabilizer (C)
according to the second invention.
[Additives]
The polycarbonate resin composition according to the second
invention may contain additives other than those described above,
for example, additives such as mold-release agents, antioxidants,
fluorescent brighteners, pigments, dyes, flame retardants, impact
resistance enhancers, antistatic agents, plasticizers,
compatibilizers, and so forth, and may contain a polymer other than
a polycarbonate resin. A single one of these additives or two or
more of these additives may be incorporated, while a single
additional resin or two or more additional resins may be
incorporated.
[Method for Producing Polycarbonate Resin Composition]
There are no limitations on the method for producing the
polycarbonate resin composition according to the present invention,
and the known methods for producing polycarbonate resin
compositions may be broadly adopted. The method can be exemplified
by preliminarily mixing, by use any of various mixers such as, for
example, a tumbler or a Henschel mixer, the polycarbonate resin
(A), ultraviolet absorber (B1) or (B2), phosphorus stabilizer (C),
and other components blended on an optional basis, followed by melt
kneading using a mixer such as a Banbury mixer, roll, Brabender,
single-screw kneading extruder, twin-screw kneading extruder,
kneader, and so forth. The melt kneading temperature is not
particularly limited, but is generally in the range from
240.degree. C. to 320.degree. C.
A variety of molded articles can be produced from the polycarbonate
resin composition according to the present invention by pelletizing
the polycarbonate resin composition described in the preceding and
molding the pellets using any of various molding methods. In
addition, the method need not proceed through a pellet stage, and
the molded article may also be made by directly molding the resin
that has been melt kneaded in an extruder.
The transmittance measured at a wavelength of 420 nm according to
JIS K 7105 on a 2 mm-thick molded article obtained by molding the
polycarbonate resin composition according to the present invention
is preferably not more than 25%, more preferably not more than 10%,
even more preferably not more than 5%, and particularly preferably
not more than 1%. When the transmittance at a wavelength of 420 nm
exceeds 25%, the performance as a material intended to block the
400 to 420 nm wavelength region, e.g., as a sunglass lens and so
forth, is then unsatisfactory.
Molded articles obtained from the polycarbonate resin composition
according to the present invention exhibit an excellent ability to
block ultraviolet light as well as light at wavelengths of 400 to
420 nm, which is on the visible light side therefrom; are free of
the problem of gas generation during molding; and have the various
excellent mechanical and thermal properties exhibited by
polycarbonate resins. They can therefore be broadly and
advantageously used in applications where ultraviolet
radiation-induced deterioration is a concern, for example, for
sheet, film, general goods, components for consumer electronics and
electrical appliances, automotive parts, building materials, hollow
containers, and so forth. More specifically, eyeglass lenses,
sunglass lenses, goggles (for skiing), protective eyeglasses,
protective masks, and so forth; roof panels for arcades, indoor
pools, carports, sun roofs, and so forth; as well as signal lamps,
sound insulating walls, side windows and rear windows for
automobiles, solar cell housings, street lamp covers, and so forth,
are preferred examples.
EXAMPLES
The present invention is more specifically described in the
following using examples. However, the present invention should not
be construed as being limited to or by the following examples.
Examples and Comparative Examples for First Invention
The starting materials and evaluation methods used in the following
examples and comparative examples for the first invention are as
follows.
TABLE-US-00001 TABLE 1 component designation polycarbonate
bisphenol A aromatic polycarbonate resin A-1 resin (A) Mitsubishi
Engineering-Plastics Corporation product name: "Iupilon (registered
trademark) S-3000" viscosity-average molecular weight Mv: 22,000
ultraviolet 6-(5-chloro-2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol
B1-1 absorber (B1) Shipro Kasei Kaisha, Ltd. maximum absorption
wavelength: 378 nm ultraviolet
6-(2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol B2-1 absorber (B2)
Shipro Kasei Kaisha, Ltd. maximum absorption wavelength: 368 nm
ultraviolet
2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(t-butyl)phenol -
B3-1 absorber (B3) BASF, product name: "Tinuvin 326" maximum
absorption wavelength: 355 nm
2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole B3-2 Shipro Kasei
Kaisha, Ltd., product name: "SEESORB 709" maximum absorption
wavelength: 344 nm 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)- B3-3
4-(1,1,3,3-tetramethylbutyl)phenol] ADEKA Corporation, product
name: "ADK STAB LA-31" maximum absorption wavelength: 349 nm
2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol B3-4 BASF,
product name: "Tinuvin 1577FF" maximum absorption wavelength: 274
nm 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) B3-5 Cytec,
product name: "Cyasorb UV3638" maximum absorption wavelength: 348
nm tetraethyl 2,2'-(1,4-phenylenedimethylidene)bismalonate B3-6
Clariant Japan KK, product name: "Hostavin B-CAP" maximum
absorption wavelength: 320 nm phosphorus
bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite C-1
stabilizer (C) ADEKA Corporation, product name: "ADK STAB PEP-36"
bis(2,4-dicumylphenyl) pentaerythritol diphosphite Dover Chemical
Corporation, C-2 product name: "DOVERPHOS S-9228PC" phenolic
octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate D-1
stabilizer (D) ADEKA Corporation, product name: "ADK STAB
AO-50"
With regard to the maximum absorption wavelength for the
ultraviolet absorber given in Table 1, the absorbance A.sub..lamda.
was determined for the composition provided by the incorporation of
0.005% of the particular ultraviolet absorber into the
polycarbonate resin given in Table 1, and the absorbance
A.sub..lamda.0 was determined for the polycarbonate resin given in
Table 1 without the incorporation of the ultraviolet absorber. The
maximum absorption wavelength is obtained from the absorption curve
for the (A.sub..lamda.-A.sub..lamda.0) absorbance provided by
subtracting the absorbance A.sub..lamda.0 from the absorbance
A.sub..lamda.. The measurement of the absorbance A.sub..lamda. and
the absorbance A.sub..lamda.0 was carried out using the method
described below in [Measurement of Transmittance and
Absorbance].
Examples 1 to 22 and Comparative Examples 1 to 9
[Production of Resin Composition Pellets]
The components given in Table 1 were blended in the proportions
(parts by mass) indicated in Tables 2 to 4 and were mixed for 20
minutes with a tumbler. This was followed by melt kneading at a
cylinder temperature of 280.degree. C. with a vented single-screw
extruder having a screw diameter of 40 mm ("VS-40" from Tanabe
Plastics Machinery Co., Ltd.) and production of pellets of the
polycarbonate resin composition by strand cutting.
[Measurement of Transmittance and Absorbance]
The obtained pellets were dried for 5 hours at 120.degree. C. using
a hot-air circulation dryer followed by the molding of stepped flat
plate-shaped test specimens of width 50 mm.times.length 90
mm.times.three thickness stages of 1 mm, 2 mm, and 3 mm. The
molding was performed with an injection molder ("SE50DUZ" from
Sumitomo Heavy Industries, Ltd.) using conditions of a resin
temperature of 280.degree. C., a mold temperature of 80.degree. C.,
and a mold cycle of 30 seconds.
The transmittance and absorbance were measured according to JIS K
7105 on the 2 mm-thick region of the stepped flat plate-shaped test
specimen using a spectrophotometer ("UV-3100PC" from the Shimadzu
Corporation).
The transmittance (unit: %) at 420 nm, 380 nm, and 320 nm is given
in Tables 2 to 4.
[Evaluation of Gas Generation During Molding]
The obtained pellets were dried for 5 hours at 120.degree. C. and
were subsequently injection molded for 100 shots using an injection
molder ("SE18DUZ" from Sumitomo Heavy Industries, Ltd.) and the
drop-shaped mold shown in FIG. 1 and using conditions of a cylinder
temperature of 320.degree. C., a mold cycle of 10 seconds, and a
mold temperature of 80.degree. C. After completion, the gas
generation during molding was evaluated by visually evaluating and
scoring, by use of the following criteria based on a comparison
with Comparative Example 2, the state of contamination by white
deposits generated on the metal mirror surface on the mold cavity
side.
A: Mold deposition is much less than the condition after molding
for 100 shots in Comparative Example 2 and the resistance to mold
contamination is thus very good.
B: Mold deposition is less than the condition after molding for 100
shots in Comparative Example 2 and resistance to mold contamination
is seen to some degree.
C: Mold deposition is on the same level as the condition after
molding for 100 shots in Comparative Example 2 and mold
contamination is thus observed.
D: Mold deposition is larger than the condition after molding for
100 shots in Comparative Example 2 and mold contamination is thus
observed to a substantial degree.
Comparative Example 2 has the same level of mold deposition as
Comparative Example 13 according to the second invention,
infra.
With reference to the drop-shaped mold in FIG. 1, the resin
composition is introduced through the gate G, and the mold is
designed to facilitate the collection of generated gas in the tip
region P. The gate G has a width of 1 mm and a thickness of 1 mm;
in FIG. 1, the width h1 is 14.5 mm, the length h2 is 7 mm, the
length h3 is 27 mm, and the thickness of the mold region is 3
mm.
The results of the preceding evaluations are given in Tables 2 to
4.
TABLE-US-00002 TABLE 2 example component 1 2 3 4 5 6 7 8 9 10 11
A-1 100 100 100 100 100 100 100 100 100 100 100 B1-1 0.07 0.07 0.07
0.07 0.08 0.07 0.07 0.05 0.05 0.04 0.03 B2-1 0.03 0.03 B3-1 0.05
B3-2 0.05 0.05 0.05 0.05 0.1 0.1 0.1 B3-3 B3-4 B3-5 B3-6 C-1 0.1
0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 C-2 D-1 0.05 0.05 0.05
transmittance 0.6 0.6 0.6 0.5 0.3 0.3 0.3 2.5 2.5 10 20 (%) at 420
nm transmittance 0 0 0 0 0 0 0 0 0 0 0 (%) at 380 nm transmittance
0.4 0 0 0 0 0 0 1.4 0 0 0 (%) at 320 nm gas generation A A A A A A
A A A A A during molding
TABLE-US-00003 TABLE 3 example component 12 13 14 15 16 17 18 19 20
21 22 A-1 100 100 100 100 100 100 100 100 100 100 100 B1-1 0.1 0.5
0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 B2-1 B3-1 B3-2 0.05
0.05 0.05 B3-3 0.05 B3-4 0.05 B3-5 0.05 B3-6 0.05 C-1 0.1 0.1 0.1
0.1 0.1 0.1 C-2 0.1 0.1 0.1 D-1 0.05 0.05 0.05 transmittance 0.1 0
0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 (%) at 420 nm transmittance 0 0
0 0 0 0 0 0 0 0 0 (%) at 380 nm transmittance 0 0 0.4 0 0 0.4 0 0 0
0 0 (%) at 320 nm gas generation A B A A A A A A A A A during
molding
TABLE-US-00004 TABLE 4 comparative example component 1 2 3 4 5 6 7
8 9 A-1 100 100 100 100 100 100 100 100 100 B1-1 0.01 2 B2-1 0.03
B3-1 0.05 0.5 2 4.5 B3-2 0.3 2 B3-3 B3-4 B3-5 B3-6 C-1 0.1 0.1 0.1
0.1 0.1 0.1 0.1 0.1 0.1 C-2 D-1 trans- 70 0 72 82 53 13 1 90 80
mittance (%) at 420 nm trans- 50 0 3 0 0 0 0 0 0 mittance (%) at
380 nm trans- 20 0 10 0 0 0 0 0 0 mittance (%) at 320 nm gas A C A
A B C D B B generation during molding
Examples and Comparative Examples for Second Invention
The starting materials and evaluation methods used in the following
examples and comparative examples for the second invention are as
follows.
TABLE-US-00005 TABLE 5 component designation polycarbonate
bisphenol A aromatic polycarbonate resin A-1 resin (A) Mitsubishi
Engineering-Plastics Corporation product name: "Iupilon (registered
trademark) S-3000" viscosity-average molecular weight Mv: 22,000
ultraviolet 6-(2H-benzotriazol-2-yl)benzo[1,3]dioxol-5-ol B2-1
absorber Shipro Kasei Kaisha, Ltd. (B2) maximum absorption
wavelength: 368 nm
6-(5-n-heptylcarbonyloxyethyl-2H-benzotriazol-2-yl) B2-2
benzo[1,3]dioxol-5-ol Shipro Kasei Kaisha, Ltd. maximum absorption
wavelength: 372 nm
6-(5-isoheptylcarbonyloxyethyl-2H-benzotriazol-2-yl) B2-3
benzo[1,3]dioxol-5-ol Shipro Kasei Kaisha, Ltd. maximum absorption
wavelength: 372 nm ultraviolet
2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(t-butyl)phenol -
B3-1 absorber BASF, product name: "Tinuvin 326" (B3) maximum
absorption wavelength: 355 nm
2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole B3-2 Shipro Kasei
Kaisha, Ltd., product name: "SEESORB 709" maximum absorption
wavelength: 344 nm
2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3- B3-3
tetramethylbutyl)phenol] ADEKA Corporation, product name: "ADK STAB
LA-31" maximum absorption wavelength: 349 nm
2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol B3-4 BASF,
product name: "Tinuvin 1577FF" maximum absorption wavelength: 274
nm 2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) B3-5 Cytec,
product name: "Cyasorb UV3638" maximum absorption wavelength: 348
nm tetraethyl 2,2'-(1,4-phenylenedimethylidene)bismalonate B3-6
Clariant Japan KK, product name: "Hostavin B-CAP" maximum
absorption wavelength: 320 nm phosphorus
bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite C-1
stabilizer ADEKA Corporation, product name: "ADK STAB PEP-36" (C)
bis(2,4-dicumylphenyl) pentaerythritol diphosphite C-2 Dover
Chemical Corporation, product name: "DOVERPHOS S-9228PC" phenolic
octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate D-1
stabilizer (D) ADEKA Corporation, product name: "ADK STAB
AO-50"
With regard to the maximum absorption wavelength for the
ultraviolet absorber given in Table 5, the absorbance A.sub..lamda.
was determined for the composition provided by the incorporation of
0.005% of the particular ultraviolet absorber into the
polycarbonate resin given in Table 5, and the absorbance
A.sub..lamda.0 was determined for the polycarbonate resin given in
Table 5 without the incorporation of the ultraviolet absorber. The
maximum absorption wavelength is obtained from the absorption curve
for the (A.sub..lamda.-A.sub..lamda.0) absorbance provided by
subtracting the absorbance A.sub..lamda.0 from the absorbance
A.sub..lamda.. The measurement of the absorbance A.sub..lamda. and
the absorbance A.sub..lamda.0 was carried out using the method
described below in [Measurement of Transmittance and
Absorbance].
Examples 23 to 45 and Comparative Examples 10 to 21
[Production of Resin Composition Pellets]
The components given in Table 5 were blended in the proportions
(parts by mass) indicated in Table 6 and were mixed for 20 minutes
with a tumbler. This was followed by melt kneading at a cylinder
temperature of 280.degree. C. with a vented single-screw extruder
having a screw diameter of 40 mm ("VS-40" from Tanabe Plastics
Machinery Co., Ltd.) and production of pellets of the polycarbonate
resin composition by strand cutting.
[Measurement of Transmittance and Absorbance]
The obtained pellets were dried for 5 hours at 120.degree. C. using
a hot-air circulation dryer followed by the molding of stepped flat
plate-shaped test specimens of width 50 mm.times.length 90
mm.times.three thickness stages of 1 mm, 2 mm, and 3 mm. The
molding was performed with an injection molder ("SE50DUZ" from
Sumitomo Heavy Industries, Ltd.) using conditions of a resin
temperature of 280.degree. C., a mold temperature of 80.degree. C.,
and a mold cycle of 30 seconds.
The transmittance and absorbance were measured according to JIS K
7105 on the 2 mm-thick region of the stepped flat plate-shaped test
specimen using a spectrophotometer ("UV-3100PC" from the Shimadzu
Corporation).
The transmittance (unit: %) at 420 nm, 380 nm, and 320 nm is given
in Table 6.
[Evaluation of Gas Generation During Molding]
The obtained pellets were dried for 5 hours at 120.degree. C. and
were subsequently injection molded for 100 shots using an injection
molder ("SE18DUZ" from Sumitomo Heavy Industries, Ltd.) and the
drop-shaped mold shown in FIG. 1 and using conditions of a cylinder
temperature of 320.degree. C., a mold cycle of 10 seconds, and a
mold temperature of 80.degree. C. After completion, the gas
generation during molding was evaluated by visually evaluating and
scoring, by use of the following criteria based on a comparison
with Comparative Example 13, the state of contamination by white
deposits generated on the metal mirror surface on the mold cavity
side.
A: Mold deposition is much less than the condition after molding
for 100 shots in Comparative Example 13 and the resistance to mold
contamination is thus very good.
B: Mold deposition is less than the condition after molding for 100
shots in Comparative Example 13 and resistance to mold
contamination is seen to some degree.
C: Mold deposition is on the same level as the condition after
molding for 100 shots in Comparative Example 13 and mold
contamination is thus observed.
D: Mold deposition is larger than the condition after molding for
100 shots in Comparative Example 13 and mold contamination is thus
observed to a substantial degree.
Comparative Example 13 has the same level of mold deposition as
Comparative Example 2 according to the first invention, supra.
With reference to the drop-shaped mold in FIG. 1, the resin
composition is introduced through the gate G, and the mold is
designed to facilitate the collection of generated gas in the tip
region P. The gate G has a width of 1 mm and a thickness of 1 mm;
in FIG. 1, the width h1 is 14.5 mm, the length h2 is 7 mm, the
length h3 is 27 mm, and the thickness of the mold region is 3
mm.
The results of the preceding evaluations are given in Table 6.
TABLE-US-00006 TABLE 6 example component 23 24 25 26 27 28 29 30 31
32 A-1 100 100 100 100 100 100 100 100 100 100 B2-1 0.09 0.15 0.25
0.5 0.07 0.07 0.1 0.1 B2-2 0.4 0.02 0.05 B2-3 0.4 0.02 0.05 B3-1
B3-2 B3-3 B3-4 B3-5 B3-6 C-1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
0.1 C-2 D-1 transmittance 20 10 0.9 0 0.1 0.2 20 20 10 10 (%) at
420 nm transmittance 0 0 0 0 0 0 0 0 0 0 (%) at 380 nm
transmittance 0 0 0 0 0 0 0 0 0 0 (%) at 320 nm gas generation A B
B B B B A A B B during molding
TABLE-US-00007 TABLE 7 example component 33 34 35 36 37 38 39 40 41
42 43 44 45 A-1 100 100 100 100 100 100 100 100 100 100 100 100 100
B2-1 0.09 0.09 0.09 0.09 0.07 0.07 0.09 0.15 0.09 0.09 0.09 0.09
0.09 B2-2 0.02 B2-3 0.02 B3-1 0.15 B3-2 0.15 0.15 0.15 0.15 B3-3
0.15 B3-4 0.15 B3-5 0.15 B3-6 0.15 C-1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
0.1 0.1 C-2 0.1 D-1 0.05 0.05 0.05 0.05 transmittance 20 20 20 20
20 20 20 10 20 20 20 20 20 (%) at 420 nm transmittance 0 0 0 0 0 0
0 0 0 0 0 0 0 (%) at 380 nm transmittance 0 0 0 0 0 0 0 0 0 0 0 0 0
(%) at 320 nm gas generation A A B B B B A B B B B B B during
molding
TABLE-US-00008 TABLE 8 comparative example component 10 11 12 13 14
15 16 17 18 19 20 21 A-1 100 100 100 100 100 100 100 100 100 100
100 100 B2-1 0.06 2 B2-2 0.07 2 B2-3 0.07 2 B3-1 0.05 0.5 2 4.5
B3-2 0.05 0.3 B3-3 B3-4 B3-5 B3-6 C-1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
0.1 0.1 0.1 0.1 0.1 C-2 D-1 transmittance 30 30 30 0 0 0 82 53 13 1
90 90 (%) at 420 nm transmittance 0 0 0 0 0 0 0 0 0 0 13 0 (%) at
380 nm transmittance 1 1 1 0 0 0 0 0 0 0 0 0 (%) at 320 nm gas
generation A A A C C C A B C D A B during molding
INDUSTRIAL APPLICABILITY
Molded articles obtained from the polycarbonate resin composition
according to the present invention exhibit an excellent ability to
block ultraviolet light as well as light on the visible light side
therefrom at wavelengths of 400 to 420 nm; are free of the problem
of gas generation during molding; and have the various excellent
mechanical and thermal properties exhibited by polycarbonate
resins. They can therefore be advantageously used in applications
where ultraviolet radiation-induced deterioration is a concern and
thus have a high level of industrial applicability.
* * * * *